CN114778514B - Measuring device and method for nondestructive high aspect ratio structure based on Raman analysis - Google Patents

Abstract

The present disclosure relates to a non-destructive measurement device and method of a high aspect ratio structure based on Raman analysis, the device comprising: a laser light source emitting a laser beam; a focusing component focusing the laser beam above a movable stage and making the focal plane of the focusing component at an initial position, and controlling the focal plane to move from the initial position to the bottom surface of a hole to be measured during the measurement process; the movable stage carries a sample to be measured and can move in a plane perpendicular to the main axis of the optical path, the axial direction of the hole to be measured in the sample to be measured is parallel to the main axis of the optical path and the hole to be measured is at a position corresponding to the focal area of the laser beam; a detection module collects the Raman scattering signal returned by the incident sample to be measured, and determines the structural parameters of the hole to be measured based on the collection results. The high aspect ratio structure can be measured quickly and non-destructively, which is helpful for efficiently evaluating the processing quality and microstructure characteristics, and provides a basis for improving the process yield and optimizing the process conditions.

Description

Device and method for measuring non-destructive high aspect ratio structures based on Raman analysis

Technical Field

The present disclosure relates to the field of measurement technology, and in particular to a device and method for measuring a lossless high aspect ratio structure based on Raman analysis.

Background technique

With the advancement of integrated circuits, micro-electromechanical systems, and 3D printing manufacturing technologies, high aspect ratio microstructures have been widely used, and the requirements for high aspect ratio microstructure measurement technology have also been continuously improved. Among the micro-nano structure measurement methods in related technologies, step profilers and atomic force microscopes (AFM) have limited measurement ranges for high aspect ratio structures; scanning electron microscopes (SEMs) have high measurement accuracy, but the sample to be measured needs to be cut open from the side, which is highly destructive; the white light or near-infrared light beams used in the measurement technology developed based on the principle of light wave interference are easily blocked and modulated by the side walls of the high aspect ratio structure, resulting in reduced resolution. In order to improve the quality and yield of device manufacturing, it is still necessary to develop fast, convenient, and non-destructive methods for measuring high aspect ratio structures.

Summary of the invention

In view of this, the present disclosure proposes a non-destructive high aspect ratio structure measurement device and method based on Raman analysis.

According to one aspect of the present disclosure, there is provided a non-destructive high aspect ratio structure measurement device based on Raman analysis, characterized in that it is used to measure the structural parameters of a hole to be measured in a sample to be measured, and the device comprises: a laser light source, a focusing component, a movable stage, and a detection module;

The laser light source is used to emit a laser beam;

The focusing component is used to converge the laser beam so that the laser beam is focused above the movable stage and the focal plane of the focusing component is located at an initial position, and control the focal plane to move from the initial position to at least the bottom surface of the hole to be measured during the measurement process;

The movable stage is used to carry the sample to be tested and can move in a plane perpendicular to the main axis of the optical path of the light focusing component. The axial direction of the hole to be tested in the sample to be tested is parallel to the main axis of the optical path and the hole to be tested is located at a position corresponding to the focusing area of the laser beam.

The detection module is used to collect the Raman scattering signal returned after the sample to be tested scatters the laser beam, and determine the structural parameters of the hole to be tested according to the collection result.

In a possible implementation manner, the device further includes:

The adjustable iris is used to shield part of the Raman scattering signal so that the signal corresponding to the focus area in the Raman scattering signal is incident on the detection module.

In a possible implementation, the light focusing component includes: an adjustable light focusing component with an adjustable focal length,

The adjustable focusing component adjusts its focal length during the measurement process so that the focal plane moves from the initial position to at least the bottom surface of the hole to be measured.

In a possible implementation, the light focusing component includes a movable light focusing component.

The movable light focusing component can move away from or approach the movable stage along a first direction, and the first direction is parallel to the main axis of the optical path;

Wherein, during the measurement process, the movable focusing component approaches the movable stage along the first direction so that the focal plane moves from the initial position to at least the bottom surface of the hole to be measured;

The movable light focusing component comprises an optical microscope, and the main axis of the light path is the optical axis of the objective lens in the optical microscope.

In a possible implementation manner, the structural parameter includes at least one of the following: at least one of the depth of the hole to be measured, the undulation of the side wall of the hole to be measured, and the rate of change of the inner diameter of the hole to be measured.

In a possible implementation, the acquisition result includes the signal intensity of the Raman scattering signal, and determining the structural parameters of the hole to be measured according to the acquisition result includes:

Determine a scanning curve corresponding to the focal plane according to the signal strength of each of the acquisition results and a first distance that the corresponding focal plane moves toward the movable stage;

Determine a plurality of characteristic points in the scanning curve and a first distance corresponding to each of the characteristic points;

Determining the structural parameters of the hole to be measured according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured and according to each of the characteristic points and the corresponding first distance;

Among them, the Raman scattering model is created based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured; the parameters in the reference sample database are determined based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured.

In a possible implementation, determining the structural parameters of the hole to be measured according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured, each of the characteristic points and the corresponding first shift distance includes:

Determine the bottom surface maximum point and the top surface minimum point among the plurality of characteristic points according to the Raman scattering model corresponding to the hole to be measured and/or the reference sample database;

The depth of the hole to be measured is determined according to the first distances respectively corresponding to the bottom surface maximum point and the top surface minimum point.

According to another aspect of the present disclosure, a non-destructive high aspect ratio structure measurement method based on Raman analysis is provided, characterized in that it is applied to the above-mentioned measurement device, and the method comprises:

Fixing the sample to be tested on the movable stage, and making the axial direction of the hole to be tested in the sample to be tested parallel to the main axis of the optical path of the light focusing component;

Controlling the laser light source to emit a laser beam toward the sample to be tested;

Controlling the light focusing component so that the focal plane of the light focusing component is at an initial position above the movable stage;

Controlling the movable stage to move in a plane perpendicular to the main axis of the optical path so that the position of the hole to be measured coincides with the focal area of the laser beam;

During the measurement process, the light focusing component is controlled so that the focal plane moves from the initial position to at least the bottom surface of the hole to be measured;

The detection module is controlled to collect the Raman scattering signal returned after the sample to be tested scatters the laser beam, and the structural parameters of the hole to be tested are determined according to the collection result.

In a possible implementation, the method further includes:

The aperture of the adjustable iris is adjusted to shield the signals in the Raman scattering signal except the signal corresponding to the focal area, so that the signal in the Raman scattering signal corresponding to the focal area is incident on the detection module.

In a possible implementation, the method includes:

After the measurement of the current hole to be measured is completed, the movable stage is controlled to move so that the next hole to be measured is in the focusing area of the laser beam, so as to measure the next hole to be measured.

In a possible implementation manner, the structural parameter includes at least one of the following: at least one of the depth of the hole to be measured, the undulation of the side wall of the hole to be measured, and the rate of change of the inner diameter of the hole to be measured.

In a possible implementation, the acquisition result includes the signal intensity of the Raman scattering signal, and determining the structural parameters of the hole to be measured according to the acquisition result includes:

Determine a scanning curve corresponding to the focal plane according to the signal strength of each acquisition result and the first distance that the corresponding focal plane moves toward the movable stage;

Determine a plurality of characteristic points in the scanning curve and a first distance corresponding to each of the characteristic points;

Determine the structural parameters of the hole to be measured according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured, each of the characteristic points and the corresponding first shift distance;

Among them, the Raman scattering model is created based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured; the parameters in the reference sample database are determined based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured.

In a possible implementation, determining the structural parameters of the hole to be measured according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured, each of the characteristic points and the corresponding first shift distance includes:

Determine the bottom surface maximum point and the top surface minimum point among the plurality of characteristic points according to the Raman scattering model corresponding to the hole to be measured and/or the reference sample database;

The depth of the hole to be measured is determined according to the first distances respectively corresponding to the bottom surface maximum point and the top surface minimum point.

The disclosed embodiments provide a device and method for measuring non-destructive high aspect ratio structures based on Raman analysis, which performs rapid non-destructive measurement of structural parameters of a periodic array of high aspect ratio structures at the wafer level based on microscopic Raman analysis, thereby facilitating non-destructive and in-situ efficient evaluation of processing quality and microstructural features, and providing a basis for improving process yield and optimizing process conditions.

Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

FIG. 1 and FIG. 2 are schematic structural diagrams showing a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure.

FIG3 is a schematic diagram showing an optical path of a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure.

FIG. 4 is a schematic diagram showing a three-dimensional structure of a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure.

FIG. 5 is a flow chart showing a method for non-destructive measurement of a high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram showing a scanning curve in a method for non-destructive measurement of a high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure.

7A-7C are schematic diagrams showing a process of measuring a lossless high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure.

FIG. 8 is a schematic diagram showing a scanning curve in a method for non-destructive measurement of a high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure.

Detailed ways

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present disclosure.

In order to solve the technical problems existing in the related art, the embodiments of the present disclosure provide a device and method for measuring non-destructive high aspect ratio structures based on Raman analysis. The device and method can perform rapid non-destructive measurement of the structural parameters of a periodic array of high aspect ratio structures at the wafer level based on Raman analysis, which helps to non-destructively and efficiently evaluate the processing quality and microstructure characteristics in situ, and provide a basis for improving the process yield and optimizing the process conditions.

FIG1 and FIG2 show schematic diagrams of the structure of a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure. As shown in FIG1 , the device includes: a laser light source 10, a focusing component 30, a movable stage 40 and a detection module 50. The device is used to measure structural parameters of a microstructure with a high aspect ratio, such as a hole 70 to be measured on a sample 60 to be measured. Among them, the microstructure with a high aspect ratio can be a hole-shaped structure with an aspect ratio exceeding 5:1, and the depth of the microstructure with a high aspect ratio can be less than or equal to 1 micron. For example, the hole to be measured can be a wafer-level high aspect ratio silicon through hole, and the aspect ratio can be 5:1, 10:1, or 20:1.

The laser light source 10 is used to emit a laser beam L1.

The focusing component 30 is used to converge the laser beam L1 so that the laser beam L1 is focused above the movable stage 40 and the focal plane of the focusing component 30 is located at the initial position, and control the focal plane to move from the initial position to at least the bottom surface of the hole to be measured 70 during the measurement process.

The movable stage 40 is used to carry the sample to be tested 60 and can move in a plane perpendicular to the main axis of the optical path of the focusing component. The axial direction of the hole to be tested 70 in the sample to be tested 60 is parallel to the main axis of the optical path and the hole to be tested 70 is located at a position corresponding to the focusing area of the laser beam.

The detection module 50 is used to collect the Raman scattering signal R received from the sample to be tested 70 after scattering the laser beam L1, and determine the structural parameters of the hole to be tested 70 according to the collection result.

In this embodiment, the structural parameter may include a parameter that can indicate the structural characteristics of the hole to be measured, and the structural parameter may include at least one of the following: the depth of the hole to be measured, the undulation of the side wall of the hole to be measured, and the rate of change of the inner diameter of the hole to be measured. Those skilled in the art may set the structural parameter according to actual needs, and the present disclosure does not limit this.

In this embodiment, the detection module 50 can be turned on at least synchronously with the laser light source 10 to ensure that the detection module 50 can obtain the Raman scattering signal in time, and avoid the failure to collect the Raman scattering signal corresponding to the focal plane being in the initial position due to the failure to turn on the detection module 50 in time, or the focal plane being between the initial position and the movable stage due to misoperation before the measurement starts.

In this embodiment, the detection module 50 is further used to collect or determine, based on the records of the focusing component 30 itself, the first distance that the focal plane corresponding to each collected Raman scattering signal R moves toward the movable stage or the distance between the focal plane corresponding to the Raman scattering signal R and the movable stage, so as to ensure that the structural parameters of the hole to be measured 70 can be determined based on the collection results and the first distance corresponding to each collection result.

In this embodiment, the structural parameters of the hole 70 to be measured may be determined by analysis of the detection module, or may be determined by other processors based on the acquisition results and the first distance corresponding to each acquisition result, and the present disclosure does not impose any limitation on this.

In this embodiment, the range of Raman scattering signal detection performed by the detection module can be set based on the material of the hole to be measured, etc., and the mobile detection range for monitoring or recording the first distance of the focal plane movement can be set based on the target depth of the hole to be measured determined by the estimated depth or design depth of the hole to be measured. The mobile detection range needs to be greater than the target depth h, and to ensure that the Raman scattering signals corresponding to the top and bottom surfaces of the hole to be measured can be collected, the mobile detection range can be 2h. Then, the movable stage surface is set to a focal plane movement distance of zero, and the mobile detection range can be [-0.5h, 1.5h], [-1.5h, 1.5h], etc. The wavelength of the laser beam emitted by the laser light source can be set based on the measurement needs of the hole to be measured. For example, if the hole to be measured is a through silicon via with a depth of about 100 μm, the wavelength of the laser beam can be set to 532 nm, the range of Raman scattering signal detection performed by the detection module can be Raman shift (Raman Shift) 500 cm ^-1 ~ 550 cm ^-1 , and the mobile detection range can be -250 μm ~ +250 μm. It is understandable that those skilled in the art can set the detection range, mobile detection range and wavelength of the laser beam according to measurement needs, and the present disclosure does not limit this.

In a possible implementation, as shown in FIG. 2 , the device may further include: an adjustable diaphragm 20 for shielding a portion of the Raman scattering signal R so that a signal R1 corresponding to a focal area in the Raman scattering signal R is incident on the detection module 50 .

FIG3 shows a schematic diagram of the optical path of a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure. In this implementation, as shown in FIG3 , a partial signal R1 in the Raman scattering signal R can pass through the focusing component 30, pass through the aperture of the adjustable iris 20, and then be incident on the detection module 50; while another partial signal R2 in the Raman scattering signal R can pass through the focusing component 30, but cannot be incident on the detection module 50 due to the shielding of the adjustable iris 20. The adjustable iris 20 is located in the optical path between the detection module 50 and the focusing component 30. The adjustable iris can be an adjustable confocal pinhole iris, and the size of the aperture of the adjustable iris can be adjusted according to the actual shielding needs, which is not limited by the present disclosure. In this way, the spatial resolution capability of the device in the main axis direction of the optical path can be improved by setting the adjustable iris 20.

In a possible implementation, the focusing component 30 may include an adjustable focusing component with an adjustable focal length. The adjustable focusing component adjusts its own focal length during the measurement process so that the focal plane moves from the initial position to at least the bottom surface of the hole to be measured. The adjustable focusing component or the detection module can determine the first distance of the focal plane movement based on the focal length change. In this way, the focal plane position can be adjusted by the adjustable focusing component to achieve the measurement of the hole to be measured.

In a possible implementation, the light focusing component 30 includes a movable light focusing component, and the movable light focusing component can move away from or approach the movable stage 40 along a first direction, and the first direction is parallel to the main axis of the optical path. During the measurement process, the movable light focusing component approaches the movable stage 40 along the first direction, so that the movable focal plane moves from the initial position to at least the bottom surface of the hole to be measured 70.

In this implementation, the movable focusing component may include an optical microscope, and the main axis of the optical path is the optical axis of the objective lens in the optical microscope. The magnification of the objective lens may be set based on the measurement requirements of the hole to be measured. For example, if the hole to be measured is a through silicon via, the magnification of the objective lens may be 10x. It is understood that those skilled in the art may set the magnification of the objective lens according to the measurement requirements, and the present disclosure does not limit this.

In this implementation, FIG4 shows a schematic diagram of the three-dimensional structure of a non-destructive high aspect ratio structure measurement device based on Raman analysis according to an embodiment of the present disclosure. As shown in FIG4, the focal area of the laser beam L1 may refer to the area irradiated by the laser beam L1 on the surface of the sample to be measured. The closer the size of the focal area is to the size of the hole to be measured 70, the more accurate the structural parameters of the hole to be measured are.

FIG5 shows a flow chart of a method for measuring a non-destructive high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure. As shown in FIG5 , the method includes steps S11 to S16. The method uses a non-destructive high aspect ratio structure measuring device based on Raman analysis provided by an embodiment of the present disclosure to achieve non-destructive measurement of the hole to be measured. The method provided by the embodiment of the present disclosure is described below in conjunction with FIGS. 1 to 5 .

In step S11 , the sample 60 to be tested is fixed to the movable stage 40 , and the axial direction of the hole 70 to be tested in the sample 60 to be tested is parallel to the main axis Z of the optical path of the light focusing component 30 .

In step S12 , the laser light source 10 is controlled to emit a laser beam L1 toward the sample 60 to be tested.

In step S13 , the light focusing component 30 is controlled so that the focal plane of the light focusing component 30 is located at an initial position above the movable stage 40 .

In this embodiment, as shown in FIG4 , the focal plane of the light-focusing component 30 can be moved away from or close to the movable stage 40 along the main axis Z of the optical path or in a direction parallel to the main axis Z of the optical path. If the light-focusing component is an adjustable light-focusing component, the position of the focal plane can be adjusted directly by adjusting the focal length of the adjustable light-focusing component. If the light-focusing component is an optical microscope (i.e., a movable light-focusing component), in the process of adjusting the optical microscope so that the focal plane of the laser light beam L1 can be in the initial position, at least one of the following methods can be adopted: "adjusting the object distance of the optical microscope itself" and "moving the optical microscope as a whole so that the objective lens is close to or away from the movable stage 40" to finally achieve "the focal plane of the laser light beam L1 is in the initial position".

In step S14 , the movable stage 40 is controlled to move in a plane perpendicular to the optical path main axis Z, so that the position of the hole to be measured 70 coincides with the focal area of the laser beam L1 .

In this embodiment, as shown in FIG. 4 , the movable stage 40 can translate on the plane where the XY axis is located (ie, the plane perpendicular to the optical axis Z), thereby changing the relative position relationship between the hole to be measured 70 and the focusing area of the laser beam L1 .

In a possible implementation, if the device includes an adjustable iris 20, then before executing step S15, the method may further include: adjusting the aperture of the adjustable iris 20 to block the signal R2 in the Raman scattering signal R except the signal R1 corresponding to the focal area, so that the signal R1 in the Raman scattering signal R corresponding to the focal area is incident on the detection module 50.

In step S15 , during the measurement process, the light focusing component 30 is controlled so that the focal plane of the light focusing component 30 moves from the initial position to at least the bottom surface of the hole to be measured 70 .

In step S16, the detection module 50 is controlled to collect the Raman scattering signal received from the sample to be measured 60 after scattering the laser beam L1 during the measurement process, and determine the structural parameters of the hole to be measured 70 according to the collected measurement results.

In a possible implementation, the acquisition result may include the signal intensity of the Raman scattering signal, and step S16 executed by the detection module 50 may include: determining a scanning curve corresponding to the focal plane according to the signal intensity of each acquisition result and the first distance that the corresponding focal plane moves toward the movable stage; determining multiple feature points in the scanning curve and the first distance corresponding to each feature point; determining the structural parameters of the hole to be measured according to the Raman scattering model and/or reference sample database corresponding to the hole to be measured, each of the feature points and their corresponding first distances.

Among them, the Raman scattering model is created based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured; the parameters in the reference sample database are determined based on the reflection and/or scattering law of the laser beam by the structure matching the hole to be measured.

In a possible implementation, the scanning curve may be preprocessed before determining the plurality of characteristic points in the scanning curve and the first distances corresponding to each of the characteristic points. The preprocessing includes at least one of smoothing processing and fitting processing. In this way, the accuracy of the determined structural parameters can be improved.

In this implementation, the Raman scattering model of the predicted scanning curve corresponding to different types of holes to be measured can be simulated in advance based on the reflection and/or scattering law of the laser beam by different types of holes to be measured (i.e., structures), so as to determine the structural parameters according to the model and the actually generated scanning curve. Alternatively, the parameter characteristics of the predicted scanning curves of different types of holes to be measured can be calculated in advance based on the reflection and/or scattering law of the laser beam by different types of holes to be measured, and a reference sample database can be established, and then the structural parameters can be determined directly based on the parameter characteristics of the predicted scanning curve recorded in the reference sample database and compared with the actual scanning curve.

In a possible implementation, determining the structural parameters of the hole to be measured according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured, each of the characteristic points and the corresponding first displacement distance may include:

Determine the bottom surface maximum point and the top surface minimum point among the multiple feature points according to the Raman scattering model and/or the reference sample database corresponding to the hole to be measured; determine the depth of the hole to be measured according to the first distances respectively corresponding to the bottom surface maximum point and the top surface minimum point.

For example, FIG6 shows a schematic diagram of a scanning curve in a method for measuring a non-destructive high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure. The detection module 50 can determine a scanning curve Q corresponding to the focal plane regarding the first distance and signal intensity as shown in FIG6 based on the signal intensity of each Raman scattering signal and the first distance of the focal plane movement detected (or recorded by the focusing component), and then determine the bottom maximum point B and the top minimum point A in the scanning curve Q based on the corresponding Raman scattering model and/or the reference sample database, and the corresponding movement distances S1=-136.1 and S2=118.5, respectively, and the depth H=|S2-S1|=|118.5-(-136.1)|=254.6μm of the hole 70 to be measured can be determined.

7A-7C are schematic diagrams showing the measurement process of a non-destructive high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure. To illustrate the measurement process of measuring the hole to be measured according to the embodiment of the present disclosure, the following is described in conjunction with FIG. 7A-7C. The laser beam L1 is converged by the focusing component 30, and in the process of the focal plane moving. As shown in FIG. 7A, the focal plane is close to the upper surface of the sample to be measured 60 and the size of the projection of the spot of the laser beam L1 on the upper surface (that is, the focusing area) is the same as the size of the hole to be measured 70. The laser beam L1 enters the hole to be measured 70 in its entirety, and the Raman scattering signal in the area corresponding to the hole to be measured 70 on the upper surface of the sample to be measured 60 gradually decreases and disappears, and the top surface minimum point A shown in FIG. 6 appears on the scanning curve. As shown in FIG. 7B, as the focal plane gradually descends until the laser beam L1 re-irradiates the surface of the side wall of the hole to be measured 70, the signal intensity of the reflected light and the Raman scattering signal increases. As shown in FIG7C , when the focal plane approaches the bottom surface of the hole to be measured 70, the laser beam L1 entering the hole to be measured 70 is completely irradiated on the bottom surface of the hole to be measured 70, and a bottom surface maximum point B appears on the scanning curve. The difference between the bottom surface maximum point B and the top surface minimum point A is the depth of the hole to be measured 70.

In this embodiment, if the sample to be tested includes multiple holes to be tested, array scanning can be used to achieve measurement of some or all of the multiple holes to be tested. The array scanning includes: after completing the measurement of each hole to be measured using the measurement process of Figures 7A to 7C above, adjusting the relative position of the movable stage 40 and the focusing component 30 in a plane perpendicular to the main axis of the optical path and controlling the focusing component 30 so that the focal plane is away from the movable stage 40, so that the focal plane of the laser beam L1 is in the initial position and the focusing area reaches the position of the next hole to be measured, and repeating the measurement process of Figures 7A to 7C above until the measurement of all holes to be measured is completed.

In this embodiment, if the sample to be tested includes multiple holes to be tested, some or all of the holes to be tested can be measured as needed. Among them, the measurement of some of the holes to be tested can be to perform interval measurement on multiple holes to be tested, that is, after measuring the current hole to be tested, the next hole to be tested is another hole to be tested that is one hole to be tested apart from the measured hole to be tested. The measurement of some of the holes to be tested can be to measure a designated hole to be tested among multiple holes to be tested, that is, a designated multiple holes to be tested among multiple holes to be tested can be measured, and the designated holes to be tested can be set by presetting the position of the designated holes to be tested, and then the measurement is realized. Those skilled in the art can set the implementation method of measuring some of the multiple holes to be tested according to actual needs, and the present disclosure does not limit this.

Among them, if the sample to be tested includes multiple holes to be tested, the device can also record and measure the moving distance of the movable stage 40 in the X-axis and Y-axis directions between different holes to be tested, and then determine the relative position relationship between the multiple holes to be tested based on the moving distance in the X-axis and Y-axis directions.

Among them, if the sample to be tested includes multiple holes to be tested, after the device calculates the structural parameters of each hole to be tested, it can also evaluate the uniformity of the structural parameters based on the structural parameters of each hole to be tested. For example, the uniformity of the hole depth can be evaluated based on the depth of each hole to be tested.

For holes with periodic fluctuations on the inner wall, this method can achieve accurate measurement of the inner wall fluctuations with the help of Raman scattering models and/or reference sample databases. However, for holes with complex structures or extremely high aspect ratios, the Raman scattering model and/or reference sample database are relatively complex. Raman scattering models can be established through standard samples, and high-precision fitting and precise fitting analysis and measurement can be achieved through big data methods such as machine learning.

For example, FIG8 shows a schematic diagram of a scanning curve in a method for measuring a non-destructive high aspect ratio structure based on Raman analysis according to an embodiment of the present disclosure. As shown in FIG8 , the aspect ratio of the hole to be measured is approximately 10:1. If a scanning curve Q' as shown in FIG8 is obtained. Then, based on the Raman scattering model and/or the reference sample database, each of the characteristic points and their corresponding first distances, the structural parameters can be determined. For example, if it is determined that the bottom surface maximum point B and the top surface minimum point A in the scanning curve Q' correspond to the top surface and bottom surface of the hole to be measured, respectively, then since the first distances between the two are S1 = -145 μm and S2 = 130 μm, the depth H = |S2-S1| = |130-(-145)| = 275 μm of the hole to be measured 70 can be determined. Combined with C1, C2, and C3, other structural parameters of the hole to be measured can be further determined.

It should be noted that, although the above embodiments are used as examples to introduce the non-destructive high aspect ratio structure measurement device and method based on Raman analysis, those skilled in the art will understand that the present disclosure should not be limited thereto. In fact, users can flexibly set each module and step according to personal preferences and/or actual application scenarios, as long as they comply with the technical solution of the present disclosure.

In some embodiments, the functions or modules included in the device provided by the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

The embodiment of the present disclosure also provides a computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the steps of determining the structural parameters of the hole to be measured according to the acquisition results in the above method are implemented. The computer-readable storage medium can be a volatile or non-volatile computer-readable storage medium.

The embodiment of the present disclosure also proposes an electronic device, comprising: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to implement the step of determining the structural parameters of the hole to be measured based on the acquisition results in the above method when executing the instructions stored in the memory.

The embodiment of the present disclosure also provides a computer program product, including a computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code. When the computer-readable code runs in a processor of an electronic device, the processor in the electronic device executes the step of determining the structural parameters of the hole to be measured based on the acquisition results in the above method.

The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (9)

1. A measurement device for a nondestructive high aspect ratio structure based on raman analysis, which is used for measuring structural parameters of a hole to be measured in a sample to be measured, the device comprising: the device comprises a laser light source, a light condensing part, a movable objective table and a detection module;

the laser light source is used for emitting laser beams;

the focusing component is used for converging the laser beam to enable the laser beam to be focused above the movable object stage, enabling the focal plane of the focusing component to be located at an initial position, and controlling the focal plane to move from the initial position to at least the bottom surface of the hole to be measured in the measuring process;

the movable objective table is used for bearing the sample to be measured and can move on a plane perpendicular to the light path main shaft of the light focusing component, the axial direction of a hole to be measured in the sample to be measured is parallel to the light path main shaft, and the hole to be measured is positioned at a position corresponding to the focusing area of the laser beam;

the detection module is used for collecting the Raman scattering signals returned after the received sample to be detected scatters the laser beam, and determining the structural parameters of the hole to be detected according to the collection result;

the acquisition result comprises the signal intensity of the Raman scattering signal, and the structural parameters of the hole to be detected are determined according to the acquisition result, and the method comprises the following steps:

determining a scanning curve corresponding to the focal plane according to the signal intensity of each acquisition result and the first distance of the corresponding focal plane moving towards the movable object stage;

determining a plurality of characteristic points in the scanning curve and first distances corresponding to the characteristic points respectively;

determining structural parameters of the hole to be detected according to the Raman scattering model and/or the reference database corresponding to the hole to be detected, the characteristic points and the corresponding first distances;

the Raman scattering model is created according to the reflection and/or scattering rule of the laser beam by a structure matched with the hole to be detected; parameters in the reference database are determined according to reflection and/or scattering rules of the laser beam by a structure matched with the hole to be detected;

the method for determining the structural parameters of the hole to be measured according to the raman scattering model and/or the reference database corresponding to the hole to be measured, each characteristic point and the corresponding first distance, comprises the following steps: determining a bottom surface maximum value point and a top surface minimum value point in the plurality of characteristic points according to the Raman scattering model and/or the reference database corresponding to the hole to be detected; and determining the depth of the hole to be measured according to the first distances respectively corresponding to the bottom surface maximum value point and the top surface minimum value point, wherein the structural parameters comprise the depth of the hole to be measured.

2. The apparatus of claim 1, wherein the apparatus further comprises:

and the adjustable diaphragm is used for shielding part of the Raman scattering signals, so that signals corresponding to the focusing area in the Raman scattering signals are incident to the detection module.

3. The apparatus of claim 1, wherein the light condensing means comprises: an adjustable focusing component with adjustable focal length,

and the adjustable light focusing component adjusts the focal length of the adjustable light focusing component in the measuring process so that the focal plane at least moves to the bottom surface of the hole to be measured from the initial position.

4. The apparatus of claim 1, wherein the condensing member comprises a movable condensing member,

the movable light focusing component can be far away from or close to the movable object stage along a first direction, and the first direction is parallel to the main axis of the light path;

in the measuring process, the movable light focusing component is close to the movable object stage along a first direction, so that the focal plane moves from the initial position to at least the bottom surface of the hole to be measured;

the movable light focusing component comprises an optical microscope, and the main axis of the light path is the optical axis of an objective lens in the optical microscope.

5. The apparatus of any one of claims 1-4, wherein the structural parameters further comprise at least one of: the sidewall waviness of the hole to be measured and the inner diameter change rate of the hole to be measured.

6. A method for measuring a non-destructive high aspect ratio structure based on raman analysis, applied to a measuring device according to any one of claims 1 to 5, said method comprising:

fixing a sample to be measured on the movable objective table, and enabling the axial direction of a hole to be measured in the sample to be measured to be parallel to the light path main shaft of the light gathering component;

controlling a laser light source to emit a laser beam to the sample to be detected;

controlling the light condensing part such that a focal plane of the light condensing part is at an initial position above the movable stage;

controlling the movable object stage to move on a plane perpendicular to the main axis of the optical path, so that the position of the hole to be measured coincides with the focusing area of the laser beam;

in the measuring process, controlling the light focusing component to enable the focal plane to move from the initial position to at least the bottom surface of the hole to be measured;

the detection module is controlled to collect a Raman scattering signal returned after the laser beam is scattered by the received sample to be detected, and the structural parameters of the hole to be detected are determined according to the collection result;

the acquisition result comprises the signal intensity of the Raman scattering signal, and the structural parameters of the hole to be detected are determined according to the acquisition result, and the method comprises the following steps:

determining a scanning curve corresponding to the focal plane according to the signal intensity of each acquisition result and the first distance of the corresponding focal plane moving towards the movable object stage;

determining a plurality of characteristic points in the scanning curve and first distances corresponding to the characteristic points respectively;

determining structural parameters of the hole to be detected according to the Raman scattering model and/or the reference database corresponding to the hole to be detected, each characteristic point and the corresponding first distance;

the Raman scattering model is created according to the reflection and/or scattering rule of the laser beam by a structure matched with the hole to be detected; parameters in the reference database are determined according to reflection and/or scattering rules of the laser beam by a structure matched with the hole to be detected;

the method for determining the structural parameters of the hole to be measured according to the raman scattering model and/or the reference database corresponding to the hole to be measured, each characteristic point and the corresponding first distance, comprises the following steps: determining a bottom surface maximum value point and a top surface minimum value point in the plurality of characteristic points according to the Raman scattering model and/or the reference database corresponding to the hole to be detected; and determining the depth of the hole to be measured according to the first distances respectively corresponding to the bottom surface maximum value point and the top surface minimum value point, wherein the structural parameters comprise the depth of the hole to be measured.

7. The method of claim 6, wherein the method further comprises:

and adjusting the aperture of the adjustable diaphragm to shield signals except for signals corresponding to a focusing area in the Raman scattering signals, so that the signals corresponding to the focusing area in the Raman scattering signals are incident to the detection module.

8. The method according to claim 6, characterized in that the method comprises:

after the measurement of the current hole to be measured is completed, the movable objective table is controlled to move so that the next hole to be measured is in the focusing area of the laser beam, and the measurement of the next hole to be measured is performed.

9. The method according to any one of claims 6-8, wherein the structural parameters further comprise at least one of: the sidewall waviness of the hole to be measured and the inner diameter change rate of the hole to be measured.